Biology subjects

Zou, W.

Publications and source records attributed to Zou, W..

46 records · Page 3Linked to original sources

bioRxiv2020

An endoplasmic reticulum (ER) ATPase safeguards ER identity by removing ectopically localized mitochondrial proteins

Stringent targeting of membrane proteins to corresponding organelles is essential for organelle identity and functions. In addition to molecular pathways that target proteins to appropriate organelles, surveillance mechanisms clear mistargeted proteins from undesired destinations. While Msp1 functions on mitochondrial membrane to remove mistargeted proteins, the surveillance mechanism for the ER is not well understood. Here, we show that mitochondrial tail-anchored (TA) and signal-anchored (SA) proteins mislocalize to ER membrane in neurons and muscles in C. elegans catp-8 mutants. catp-8 encodes a conserved P5A type ATPase, which localizes to ER and removes ectopic mitochondrial TA/SA proteins from ER. In catp-8 mutant, mitochondria fission protein FIS-1 mislocalizes to ER membrane. Together with another mitochondria fission protein MFF-2, FIS-1 causes ER fragmentation in a Dynamin related protein (DRP-1) dependent manner. Additionally, CATP-8 is essential for dendrite development. catp-8 mutant dramatically reduces the level of the dendrite guidance receptor DMA-1, leading to diminished dendritic arbors. Hence, P5A ATPase safeguards ER morphology and functions by preventing mitochondrial proteins mislocalization. HIGHLIGHTSCATP-8, a P5A type ATPase, localizes to ER and functions as a surveillance mechanism to remove mistargeted mitochondrial proteins. Multiple mitochondria proteins are mistargeted to ER in catp-8 mutants. Ectopic recruitment of mitochondria fission mechinary to ER causes ER fragmentation in catp-8 mutants. CATP-8 is essential for PVD dendrite morphogenesis through modulating the level of transmembrane receptor DMA-1.

cell biology↗

bioRxiv2020

Relationship Between Neuroendocrine and Immune Gene Expression in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is classified as a high-grade neuroendocrine (NE) tumor, but a subset of SCLC has been termed "variant" due to the loss of NE characteristics. In this study, we computed NE scores for patient-derived SCLC cell lines and xenografts, as well as human tumors. We aligned NE properties with transcription factor-defined molecular subtypes. Then we investigated the different immune phenotypes associated with high and low NE scores. We found repression of immune response genes as a shared feature between classic SCLC and pulmonary neuroendocrine cells of the healthy lung. With loss of NE fate, variant SCLC tumors regain cell-autonomous immune gene expression and exhibit higher tumor-immune interactions. Pan-cancer analysis revealed this NE lineage-specific immune phenotype in other cancers. Additionally, we observed MHC I re-expression in SCLC upon development of chemoresistance. These findings provide a new framework to guide design of treatment regimens in SCLC.

cancer biology↗

bioRxiv2020

Glucose Production and Glucose Disposal Integrated by an Intrinsic Inverse Coupling in Vivo: hypothesis of inter-organ reflex on glucose regulation

Glucose production (GP) and glucose disposal (Rd) are two decisive and fundamental parameters in glucose turnover and in glucose homeostasis regulation. In conventional theory, GP and Rd were responsive to regulatory factors respectively and independently of each other. Even though GP and Rd responded in reverse to insulin, GP for suppression and Rd for elevation, these inverse alterations used to be attributed to insulin multiple functions both on hepatic GP, directly or indirectly, and on whole-body glucose Rd. However, in the present study, we found GP and Rd were inversely coupled intrinsically no matter which side was the target of insulin by comparison of Rd and GP data pairs between peripheral vein insulin infusion protocol and portal vein insulin infusion protocol in rats. Furthermore, neither circulating NEFA nor HFD induced resistance broke the GP-Rd inverse coupling, but both of them reduced the responses of both GP and Rd to insulin. In conclusion, we provide the evidence that GP and Rd are two coupled parameters in vivo and they alter in reverse simultaneously, the mechanism under which needs further investigation but we tend to believe an inter-organ neural reflex was involved.

physiology↗

bioRxiv2020

Heteroplasmy variability in individuals with biparentally inherited mitochondrial DNA

With very few exceptions, mitochondrial DNA (mtDNA) in humans is transmitted exclusively from mothers to their offspring, suggesting the presence of a strong evolutionary pressure favoring the exclusion of paternal mtDNA. We have recently shown strong evidence of paternal mtDNA transmission. In these rare situations, males exhibiting biparental mtDNA appear to be limited to transmitting just one of the mtDNA species to their offspring, while females possessing biparental mtDNA populations consistently transmit both populations to their offspring at a very similar heteroplasmy level. The precise biological and genetic factors underlying this unusual transmission event remain unclear. Here, we have examined heteroplasmy levels in various tissues among individuals with biparental inheritance. Our results indicate that individuals with biparental mtDNA have remarkable inter-tissue variability in heteroplasmy level. At the single-cell level, paternal mtDNA heteroplasmy in sperm varies dramatically, and many sperm possess only one of the two mtDNA populations originally in question. These results show a fundamental, parent-of-origin difference in how mtDNA molecules transmit and propagate. This helps explain how a single population of mtDNAs are transmitted from a father possessing two populations of mtDNA molecules, suggesting that some mtDNA populations may be favored over others when transmitted from the father.

genetics↗

bioRxiv2020

Human Tau Isoform Aggregation and Selective Detection of Misfolded Tau from Post-Mortem Alzheimer's Disease Brains

Tau aggregates are present in a large number of neurodegenerative diseases known as "tauopathies", including Alzheimers disease (AD). As there are six human tau isoforms in brain tissues and both 3R and 4R isoforms have been observed in the neuronal inclusions, we tested whether tau isoforms behave differently in aggregation. We discovered that all six tau isoforms are capable of forming PHF-tau like filaments and the 3R tau isoforms aggregate significantly faster than their 4R counterparts. We further mapped key segments of tau isoforms that contribute to their aggregation kinetics, where it was determined that microtubule binding domains R2 and R3 were the major contributors to tau aggregation. To evaluate the feasibility of using the six recombinant tau isoforms as substrates to amplify misfolded tau, we demonstrated that full-length human tau isoforms can seed and detect misfolded tau from the post-mortem AD brain tissues with high specificity by an ultrasensitive technology termed real-time quaking-induced conversion (RT-QuIC). Mass spectrometric analysis of PHF-tau samples extracted from AD brains identified peptides corresponding to all major forms of human brain tau isoforms along with a consensus hyperphosphorylated peptide near the C-terminus. Together, our findings not only reveal new aggregation kinetic properties of human tau isoforms, support the development of methods to quantitatively measure misfolded human tau isoforms in AD brains, but also uncover the capability of full-length human tau isoforms as substrates for "prion-like" tau seeding by RT-QuIC assays that may be used for new biomarker development for AD and other tauopathy diagnosis.

pathology↗

bioRxiv2019

ASK1/p38-mediated NLRP3 inflammasome signaling pathway contributed to aberrant retinal angiogenesis in diabetic retinopathy

AbstractsDiabetic retinopathy is the leading cause of blindness in the working-age population in many countries. Despite the available treatments, some patients present late in the course of the disease when treatment is more difficult. Hence, it is crucial that the new targets are found and utilized in clinical therapy of diabetic retinopathy. In this study, we constructed the DR animal model and the high model in HRMEC cell to investigate the relationship between ASK1/p38 and NLRP3 in DR. The results showed that DR could cause the inflammatory response and microvascular proliferation. NLRP3 contributed to DR-mediated inflammatory development and progression, which promoted the inflammatory related cytokine expression. Meanwhile, it could promote the tube formation of retinal microvascular endothelial and angiogenesis. Moreover, further research showed that NLRP3 mediated aberrant retinal angiogenesis in diabetic retinopathy was regulated by ASK1 and p38. It suggested that ASK1/p38 could become a new target in DR treatment.

cell biology↗

bioRxiv2019

Novel Pure αVβ3 Integrin Antagonists That Do Not Induce Receptor Extension, Prime the Receptor, or Enhance Angiogenesis at Low Concentrations

The integrin V{beta}3 receptor has been implicated in several important diseases, but no V{beta}3 antagonists are approved for human therapy. One possible limitation of current small-molecule antagonists is their ability to induce a major conformational change in the receptor that induces it to adopt a high-affinity ligand-binding state. In response, we used structural inferences from a pure peptide antagonist to design the small-molecule pure antagonists TDI-4161 and TDI-3761. Both compounds inhibit V{beta}3-mediated cell adhesion to V{beta}3 ligands, but do not induce the conformational change as judged by antibody binding, electron microscopy, X-ray crystallography, and receptor priming studies. Both compounds demonstrated the favorable property of inhibiting bone resorption in vitro, supporting potential value in treating osteoporosis. Neither, however, had the unfavorable property of the V{beta}3 antagonist cilengitide of paradoxically enhancing aortic sprout angiogenesis at concentrations below its IC50, which correlates with cilengitides enhancement of tumor growth in vivo.\n\nSignificance StatementV{beta}3 is a potential therapeutic target for several important human diseases, but there are currently no V{beta}3 antagonists approved for human therapy. Current candidates are primarily based on the Arg-Gly-Asp (RGD) motif and act as partial agonists in that they induce V{beta}3 to undergo a conformational change that converts it into a high-affinity ligand-binding state. We have used structure-guided design to produce pure small-molecule V{beta}3 antagonists that do not induce the conformational change as judged by protein crystallography, electron microscopy, and receptor priming. These compounds inhibit V{beta}3-mediated bone resorption in vitro, but unlike the partial agonist cilengitide, do not enhance angiogenesis at low doses, a property that correlates with low-dose cilengitides enhancement of tumor growth in vivo. These pure V{beta}3 antagonists can help define V{beta}3s role in animal models. If they demonstrate benefits over partial agonists in these model systems, they may be appropriate to consider for human therapy.

pharmacology and toxicology↗

bioRxiv2018

Gfi1-expressing Paneth cells revert to stem cells following intestinal injury

BackgroundAimChemotherapy drugs harm rapidly dividing normal healthy cells such as those lining the gastrointestinal tract, causing morbidity and mortality that complicates medical treatment modalities. Growth Factor-Independent 1 (GFI1) is a zinc finger transcriptional repressor implicated in the differentiation of secretory precursors into Paneth and goblet cells in the intestinal epithelium. We hypothesize that stimulating the reversion of Gfi1+ secretory cells into stem cells will improve intestinal epithelial regeneration and mitigate injury.\n\nMethodsGfi1 reporter mice (Gfi1cre/+; ROSA26 LSL-YFP) were treated with Doxorubicin, radiation, anti-CD3 antibody, and rotavirus to induce intestinal injury. Mice and intestinal organoids (enteroids) were used to investigate cellular repair mechanisms following injury.\n\nResultsUnder homeostatic conditions, Gfi1-lineage cells are Paneth and goblet cells, which were non-proliferative and not part of the stem cell pool. After injury, Gfi1+ secretory cells can re-enter the cell cycle and give rise to all cell lineages of the intestinal epithelium including stem cells. Reversion of Gfi1-lineage cells was observed in other injury model systems, including irradiation and anti-CD3 treatment, but not in ISC-sparing rotavirus infection. Our results also demonstrated that PI3kinase/AKT activation improved cell survival, and elevated WNT signaling increased the efficiency of Gfi1+ cell reversion upon injury.\n\nConclusionsThese findings indicate that Gfi1+ secretory cells display plasticity and reacquire stemness following severe damage. Moreover, PI3kinase/AKT and WNT are key regulators involved in injury-induced regeneration. Our studies identified potential therapeutic intervention strategies to mitigate the adverse effects of chemotherapy-induced damage to normal tissues and improve the overall effectiveness of cancer chemotherapy.

cell biology↗

bioRxiv2018

CRISPR-Tag: an Efficient DNA Tagging System in Living Cells

Main textA lack of efficient tools to image non-repetitive genes in living cells has limited our ability to explore the functional impact of spatiotemporal dynamics of genes. Here, we addressed this issue by developing the CRISPR-Tag system as a new DNA tagging strategy to label protein-coding genes with high signal-to-noise ratio under wild-field fluorescence microscopy by using 1 to 4 highly active sgRNAs. The CRISPR-Tag, with minimal size of [~] 250 bp, represents an easily and broadly applicable technique to study spatiotemporal organization of genomic elements in living cells.

cell biology↗

bioRxiv2017

Aquaporin-4 dependent glymphatic solute transport in rodent brain

The glymphatic system is a brain-wide metabolite clearance pathway, impairment of which in post-traumatic and ischemic brain or healthy aging is proposed to contribute to intracerebral accumulation of amyloid-{beta} and tau proteins. Glymphatic perivascular influx of cerebrospinal fluid (CSF) depends upon the expression and perivascular localization of the astroglial water channel aquaporin-4 (AQP4). Prompted by a recent publication that failed to find an effect of Aqp4 knockout on perivascular CSF tracer influx and interstitial fluid (ISF) tracer dispersion, four independent research groups have herein re-examined the importance of Aqp4 in glymphatic fluid transport. We concur in finding that CSF tracer influx, as well as fluorescently-tagged amyloid-{beta} efflux, are significantly faster in wild-type mice than in three different transgenic lines featuring disruption of the Aqp4 gene and one line in which AQP4 expression lacks the critical perivascular localization (Snta1 knockout). These data validate the role of AQP4 in supporting fluid and solute transport and efflux in brain in accordance with the glymphatic system model.

neuroscience↗